1. Field of the Invention
The present invention relates to an automobile weather strip. More particularly, the present invention relates to an automobile weather strip that includes at least (a) a weather strip body formed from a rubber composition and (b) a decorative layer comprising at least one thermoplastic elastomer (TPE), the decorative layer being directly adhered onto the weather strip body.
2. Description of the Related Art
Weather strips having a decorative layer, such as a trim part, have been produced in accordance with the following techniques.
A first technique involves providing a weather strip body made of a sulfur-vulcanized rubber composition formed primarily from an ethylene-propylene-diene terpolymer (EPDM) or styrenebutadiene rubber (SBR) and covering the body with a decorative layer formed from a strip cut from a polyvinyl chloride (PVC) sheet. The PVC sheet is attached to the weather strip body via an adhesive. This first technique, however, requires several time-consuming and complicated steps, such as cutting the PVC sheet into appropriately sized and shaped strips, applying an adhesive onto the weather strip body, and adhering the strip onto the weather strip body under appropriate pressure.
In order to reduce the steps in the production of weather strips, a second technique has been proposed which involves directly extruding a decorative layer comprising a non-polar thermoplastic elastomer (TPE), such as an olefinic thermoplastic elastomer (TPO) or styrenic thermoplastic elastomer (TPS), onto a weather strip body comprising EPDM or SBR. Such extruding step should take place immediately after the vulcanization of the weather strip body. Thereafter, the decorative layer is hot-sealed directly onto the weather strip body, thereby producing a weather strip coated with the decorative layer.
However, it has been found that the weather strips as produced according to this second technique become discolored or yellowed over the passage of time. In order to prevent such discoloration, an increased amount of a pigment (colorant) can be incorporated into the decorative layer to mask the discoloration. However, this approach is not applicable to light or pale colors, since light or pale colors are not sufficiently opaque to achieve such masking effect. Therefore, in view of the recent tendency toward decorative layers colored in light or pale colors, this second technique is not practicable for a variety of light and pale colors.
A need therefore exists to provide an automobile weather strip which is both economical to produce and does not undergo discoloration, particular with regard to light or pale color decorative layers.